Transport box

ABSTRACT

A transport box has a one-piece container, which has a base and walls extending from the base and delimiting a transport chamber. The container consists of particulate foam made of expanded polypropylene (EPP), which has a plurality of foam particles sintered to each other, wherein the foam particles each comprise an outer wall and a substantially hollow inner chamber enclosed by the outer wall. The outer walls of the foam particles at the inner faces of the container which delimit the transport chamber are thicker than in the remaining regions of the container and form an inner skin on the container.

The invention relates to a transport box in accordance with the preamble of claim 1.

Such transport boxes are used, in particular, for transport of foods, which must be transported in refrigerated manner, for example. In this connection, it has been shown that expanded polypropylene (EPP) combines a good thermal insulation effect with good shape retention. In particular, deformations return to their original shape by themselves, in part. During production, foam particles composed of EPP are sintered together with one another, whereby the container is produced in one mold, and the lid is produced in another mold, in one piece, in each instance. In this connection, pores remain open between the foam particles, which represent cavities or at the surfaces of which depressions remain. These depressions have a detrimental effect if such a transport box is to be re-used in the foods sector. This is because dirt can become lodged in the depressions, so that the transport box must be carefully cleaned before re-use. It has therefore already been proposed to line such transport boxes with a plastic film, but this again is complicated.

It is therefore the task of the invention to further develop a transport box of the type stated initially, in such a manner that it is even better suited for foods.

This task is accomplished, according to the invention, by means of a transport box having the characteristics of claim 1. Advantageous further developments of the invention are the object of the dependent claims.

The invention is based on the idea that in the case of thickening of the outer particle walls at the interior surfaces of the container that delimit the transport space, and, if applicable, a lid that closes off the container, a type of inner skin of the transport box is formed, which is significantly smoother than the other surfaces of the container and of the lid. By means of this skin formation, the pores become smaller and, along with them, also the depressions in the interior surfaces, so that less dirt can accumulate on the surfaces exposed to the transport goods, and this dirt can be removed again more easily.

The outer walls of the foam particles are thicker, according to the invention, at the interior surfaces that delimit the transport space than at the other locations of the container, and, if applicable, of the lid. It is preferred that they are at least twice, preferably at least three times, and ideally at least seven times as thick. A typical value for the thickness is at least 0.2 mm at the interior surfaces. By means of this measure, a reduction in size of the pores situated between the foam particles on the interior surfaces of the container that delimit the transport space and of the lid to a maximal size of 0.2 mm can be achieved.

It is practical if the container has a circumferential rim on the upper edges of the walls, and if the lid has a circumferential accommodation groove for accommodating the rim, whereby the bottom surface of the accommodation groove is intended for making contact with a contact surface of the rim. In this connection, the inner skin of the container extends over the contact surface, and the inner skin of the lid extends over the bottom surface. By means of this measure, the insulating effect of the transport box is further improved. In that the inner skin of the container extends over the contact surface, on the one hand, and the inner skin of the lid extends over the bottom surface, on the other hand, two particularly smooth surfaces lie against one another and improve the insulating effect even more.

According to an advantageous further development, it is provided that the distance between two walls of the container that lie opposite one another, in each instance, increases in the direction away from the bottom. This has the advantage that after the production process of the container, the latter can be removed more easily from the production mold. The container and the production mold come out of contact immediately after lift-off, which is particularly advantageous with regard to a smooth inner skin, which does not have to slide along the surface of the production mold when the container is removed from the latter; this could cause scratching.

The walls can be connected with the bottom by means of film hinges and can be foldable into a transport position, in which they are disposed essentially parallel to the bottom. In this connection, it is preferred that the inner skin of the container extends to cover the film hinges. This has the advantage, for one thing, that the cracks between the walls and the bottom are also lined with the inner skin and are easier to clean. For another, this measure has the advantage that the film hinges are reinforced by the inner skin. This configuration as a folding box is particularly advantageous if the transport box is to be used multiple times and must be transported empty after use. This can then take place in space-saving manner, with folded-down walls. The re-usability of the transport box, as described above, is furthermore the main reason for a configuration of the transport box with the inner skin.

The container advantageously has grooves in its bottom, in its interior surface, over the surface of which grooves the inner skin extends. The grooves serve for accommodating melt water in the case of a transport box that accommodates frozen goods, for example. The application of the inner skin to the surface of the grooves is therefore particularly advantageous, since contaminants accumulate in the grooves to a greater degree.

It is practical if the container has a depression that extends to the upper edge of the wall, in each instance, in two walls that lie opposite one another. Then, a rigid container insert can be inserted into the interior space, and can be grasped more easily in the region of the depressions. Furthermore, it is practical if the container has a recess on each edge that connects two walls with one another, for grasping below the lid, so that the latter can be lifted off the container more easily.

In the following, the invention will be explained in greater detail using exemplary embodiments shown schematically in the drawing. This shows:

FIG. 1 a transport box according to a first exemplary embodiment, in a perspective view, with the lid lifted off;

FIG. 2 the lid according to FIG. 1 from below, and

FIG. 3 a transport box according to a second exemplary embodiment, with the lid lifted off, and the walls folded halfway down.

The transport box 10 according to the first exemplary embodiment (FIG. 1) has a container 12 as well as a lid 14. The container 12 has a bottom 16 as well as four walls 18 that extend vertically upward from the rectangular bottom 16. The bottom 16 and the walls 18 delimit a transport space 20 that is open toward the top, which space can be closed off by setting the lid 14 onto the container 12.

The container 12 and the lid 14 are produced in one piece, in each instance, from a particle foam material composed of expanded polypropylene (EPP). The particle foam material has a plurality of foam particles sintered to one another, whereby the foam particles have an outer wall, in each instance, and an essentially hollow interior space enclosed by the outer wall, in which cells are situated, the skin of which is significantly thinner than the outer wall, and that either communicate with one another or are closed. Between the foam particles, there are pores that represent cavities. In order to reduce the size of the pores that are adjacent to the interior surfaces 22 of the container 12 and of the lid 14 that delimit the transport space 20, these interior surfaces 22 are treated by applying heat to them, in such a manner that the outer wall sections of the foam particles that border on them have a thickness of at least 0.2 mm, while the remaining wall thickness of the foam particles is less. As a result, an inner skin 24 is formed on the interior surfaces 22 of the container 12 and of the lid 14, in each instance.

The container 12 has a circumferential rim 26 at the upper edges of its walls 18, which rim is offset toward the inside as compared with the outer surface 28 of the walls 18, so that the container 12 has a circumferential step 30. The lid 14, as shown in FIG. 2, has a circumferential accommodation groove 32 for accommodating the rim 26, on its underside. In this connection, the inner skin 24 of the lid 14 extends all the way to a bottom surface 34 of the groove 32. The inner skin 24 of the container 12 extends all the way to a contact surface 36 of the rim 26, which surface runs horizontally.

The interior surfaces of the walls 18 run not precisely perpendicular to the interior surface of the bottom 16, but rather are inclined slightly to the outside, so that the distance between two walls 18 that lie opposite one another, in each instance, increases toward the top, proceeding from the bottom 16. In two walls 18 that lie opposite one another, a depression 38 is furthermore disposed in the center, which extends from the bottom 16 all the way to the upper edge. The two depressions 38 are configured with mirror symmetry with reference to a longitudinal center plane of the container 12. At each of the edges 40 that connect two walls 18 with one another, the step (30) has a depression 42 that allows an operator to grasp underneath the lid 14. Furthermore, the rim 26 is provided with an engagement projection 44 above the recesses 42, in each instance, by means of which projection the container 12 can be engaged into the lid 14.

The transport box 110 according to the second exemplary embodiment (FIG. 3) differs from the transport box 10 according to the first exemplary embodiment essentially in that the walls 18 can be folded down relative to the bottom 16. For this purpose, they are connected with the bottom 16, in one piece, by means of film hinges 46 that represent a thin-walled, bendable connection. The inner skin 24 extends also over the film hinges 46. Furthermore, the bottom 16 is provided with elongated grooves 48 that run parallel to one another and have the shape of a section of a cylinder, and over which the inner skin 24 also extends.

In summary, the following should be stated:

The invention relates to a transport box having a one-piece container 12 having a bottom 16 and walls 18 that extend from the bottom 16, delimiting a transport space 20, which container consists of a particle foam material composed of expanded polypropylene (EPP), which has a plurality of foam particles sintered to one another, wherein the foam particles have an outer wall, in each instance, and an essentially hollow interior space enclosed by the outer wall. According to the invention, it is provided that the outer walls of the foam particles are thicker at the interior surfaces 22 of the container 12 that delimit the transport space 20 than at the other locations of the container 12, and form an inner skin 24 on the container 12. 

1. Transport box having a one-piece container (12) having a bottom (16) and walls (18) that extend from the bottom (16), delimiting a transport space (20), which container consists of a particle foam material composed of expanded polypropylene (EPP), which has a plurality of foam particles sintered to one another, wherein the foam particles have an outer wall, in each instance, and an essentially hollow interior space enclosed by the outer wall, wherein the outer walls of the foam particles are thicker at the interior surfaces (22) of the container (12) that delimit the transport space (20) than at the other locations of the container (12), and form an inner skin (24) on the container (12).
 2. Transport box according to claim 1, comprising a one-piece lid (14) for closing off the transport space (20), which lid consists of a particle foam material composed of expanded polypropylene (EPP), which has a plurality of foam particles sintered to one another, wherein the foam particles have an outer wall, in each instance, and an essentially hollow interior space enclosed by the outer wall, wherein the outer walls of the foam particles are thicker at the interior surfaces (22) of the lid (14) that delimit the transport space than at the other locations of the lid (14), and form an inner skin (24) on the lid (14).
 3. Transport box according to claim 1, wherein the outer walls of the foam particles at the interior surfaces (22) of the container (12) and, if applicable, the lid (14) are at least twice, preferably at least three times, and ideally at least seven times as thick as at the other locations of the container (12) and the lid (14), respectively.
 4. Transport box according to claim 1, wherein the outer walls of the foam particles have a thickness of at least 0.2 mm at the interior walls (22) of the container (12) and, if applicable, of the lid (14).
 5. Transport box according to claim 1, wherein the pores situated between the foam particles have a maximal size of 0.2 mm on the interior surfaces (22) of the container (12) that delimit the transport space (20) and, if applicable, of the lid (14).
 6. Transport box according to claim 2, wherein the container (12) has a circumferential rim (26) on the upper edges of the walls (18), wherein the lid (14) has a circumferential groove (32) for accommodating the rim (26), wherein a bottom surface (34) of the accommodation groove (32) is intended for making contact with a contact surface (36) of the rim (26), and wherein the inner skin (24) of the container (12) extends over the contact surface (36), and the inner skin (24) of the lid (14) extends over the bottom surface (34).
 7. Transport box according to claim 1, wherein the distance between two walls (18) of the container (12) that lie opposite one another, in each instance, increases in the direction away from the bottom (16).
 8. Transport box according to claim 1, wherein the walls (18) are connected with the bottom (16) by means of film hinges (46) and are foldable into a transport position, in which they are disposed essentially parallel to the bottom (16).
 9. Transport box according to claim 8, wherein the inner skin (24) of the container (12) extends to cover the film hinges (46).
 10. Transport box according to claim 1, wherein the container (12) has grooves (48) in its bottom (16), on the interior surface (22) of the latter, over the surface of which grooves the inner skin (24) extends.
 11. Transport box according to claim 1, wherein the container (12) has a depression (38) that extends to the upper edge of the wall (18), in each instance, in two walls (18) that lie opposite one another.
 12. Transport box according to claim 2, wherein the container (12) has a recess (42) on each edge (40) that connects two walls (18) with one another, for grasping below the lid (14). 